<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            width: 200px;
            height: 200px;
        }
        
        .box1 {
            position: relative;
            z-index: 0;
            background-color: blanchedalmond;
        }
        
        .box2 {
            position: relative;
            top: -100px;
            left: 100px;
            z-index: 99;
            background-color: blueviolet;
        }
    </style>
</head>

<body>
    <div class="box1">盒子1</div>
    <div class="box2">盒子2</div>
</body>

</html>